X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fcontainer_of%2Fcontainer_of.h;h=2a6b1cd54e9dcf97f57b0b282e23bb7de82ae0db;hp=ec66f106f2aeb0144b17455973607b873ae88731;hb=da72623aec30213a593bd23dca80c89416598f75;hpb=a8b248ea9de55316cac4423a99a727ca7b54e0fc

diff --git a/ccan/container_of/container_of.h b/ccan/container_of/container_of.h
index ec66f106..2a6b1cd5 100644
--- a/ccan/container_of/container_of.h
+++ b/ccan/container_of/container_of.h
@@ -15,13 +15,16 @@
  * subtraction to return the pointer to the enclosing type.
  *
  * Example:
- *	struct info
- *	{
+ *	struct foo {
+ *		int fielda, fieldb;
+ *		// ...
+ *	};
+ *	struct info {
  *		int some_other_field;
  *		struct foo my_foo;
  *	};
  *
- *	struct info *foo_to_info(struct foo *foop)
+ *	static struct info *foo_to_info(struct foo *foo)
  *	{
  *		return container_of(foo, struct info, my_foo);
  *	}
@@ -42,24 +45,19 @@
  * subtraction to return the pointer to the enclosing type.
  *
  * Example:
- *	struct info
- *	{
- *		int some_other_field;
- *		struct foo my_foo;
- *	};
- *
- *	struct info *foo_to_info(struct foo *foop)
+ *	static struct info *foo_to_i(struct foo *foo)
  *	{
  *		struct info *i = container_of_var(foo, i, my_foo);
  *		return i;
  *	}
  */
-#ifdef HAVE_TYPEOF
+#if HAVE_TYPEOF
 #define container_of_var(member_ptr, var, member) \
 	container_of(member_ptr, typeof(*var), member)
 #else
-#define container_of_var(member_ptr, var, member) \
-	((void *)((char *)(member_ptr) - offsetof(containing_type, member)))
+#define container_of_var(member_ptr, var, member)		\
+	((void *)((char *)(member_ptr)				\
+		  - ((char *)&(var)->member - (char *)(var))))
 #endif
 
 #endif /* CCAN_CONTAINER_OF_H */